Obscuration map generation

ABSTRACT

A camera is arranged on a transmitter or receiver mount configured to provide a transmitter or receiver with a field of regard. Image data of the field of regard is captured by the camera. A location of an obscuration within the field of regard from the image data is determined from the image data. A map of obscurations within the field of regard is generated based upon the image data and the location of the obscuration within the field of regard.

STATEMENT OF GOVERNMENTAL INTEREST

This invention was made with U.S. Government support under contract no.N00019-15-G-0026 DO 0503 awarded by the U.S. Government. The U.S.Government has certain rights in the invention.

TECHNICAL FIELD

The present disclosure relates to the generation of obscuration maps fortransmitter and receiver systems.

BACKGROUND

An obscuration refers to a feature within a field of view or regard of atransmitter or receiver. When such transmitters or receivers areinstalled on aircraft, example obscurations include the fuselage, tailsor wings of the host aircraft which prevent the transmitter from seeingan incoming threat. Obscuration maps are included as part of, forexample, an Aircraft Characterization Module image. Such images areutilized by the control systems of the aircraft in order to reduce falsealarms, to allow the aircraft to properly allocate transmitters, andincreasing the operational life of the transmitter and receiver systems.

The current processes to create transmitter and receiver obscurationmaps utilize marking tangential points created by a laser mounted at thetransmitter or receiver's location on the aircraft. These processes aretime-consuming and labor intensive.

Obscuration maps are particularly useful in Directional InfraredCountermeasure systems which utilize sensors to detect incoming threatsand transmitters to direct infrared energy at the detected threats toneutralize the threats. Obscuration maps are used by the receiver todetermine the receiver's field of regard. Obscuration maps are also usedby the transmitters to ensure that the transmitters do not projectedinfrared energy at the aircraft or other platform to which thetransmitter is mounted.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a Directional Infrared Countermeasuretransmitter field of regard, according to an example embodiment.

FIG. 2 is an illustration of a Directional Infrared Countermeasurereceiver field of regard, according to an example embodiment.

FIG. 3 is a flowchart illustrating a first process for generating anobscuration map, according to an example embodiment.

FIG. 4 is a screen shot of a computer implemented tool that may be usedfor generating an obscuration map, according to an example embodiment.

FIG. 5 is a perspective view of a first camera mounting fixture used forgenerating an obscuration map, according to an example embodiment.

FIG. 6 is a perspective view of a second camera mounting fixture usedfor generating an obscuration map, according to an example embodiment.

FIG. 7 are front views of the first and second camera mounting fixtures,respectively, according to an example embodiment.

FIG. 8 is a flow chart illustrating a method that may be used forgenerating an obscuration map, according to an example embodiment.

FIG. 9 is a schematic diagram showing a computing system configured toimplement the techniques described herein, according to an exampleembodiment.

DESCRIPTION OF EXAMPLE EMBODIMENTS Overview

According to a first example embodiment, a camera is arranged on atransmitter or receiver mount configured to provide a transmitter orreceiver with a field of regard. Image data of the field of regard iscaptured by the camera. A location of an obscuration within the field ofregard from the image data is determined from the image data. A map ofobscurations within the field of regard is generated based upon theimage data and the location of the obscuration within the field ofregard. According to more specific example embodiments, the transmitteror receiver is a directional infrared countermeasure transmitter orreceiver.

According to a second example embodiment, an apparatus is provided thatincludes a mounting plate of a camera positioning fixture; an azimuthalangle positioning plate rotatably mounted to the mounting plate; amounting arm mounted to the azimuthal angle positioning plate andextending in a direction normal to a surface of the azimuthal anglepositioning plate; a polar positioning mount rotatably mounted to themounting arm; and a camera mount connected to the polar positioningmount and configured to secure the camera to the fixture. The mountingplate is configured to secure the camera positioning fixture to atransmitter or receiver mount; and the mounting arm, the azimuthal anglepositioning plate and the polar positioning mount are configured toposition the camera at a plurality of positions for acquisition of imagedata by the camera corresponding to a field of regard of the transmitteror a field of regard of the receiver.

According to a third example embodiment, an apparatus is provided thatincludes a communication interface; and a processor. The processor isconfigured to receive, via the communication interface; image datacorresponding to a field of regard of a transmitter or receiver;determine pixel coordinates of an obscuration in the field of regard ofthe transmitter or receiver contained in the image data; determine alocation of the obscuration relative to the transmitter or receiver bytranslating the pixel coordinates to coordinates relative to a locationof the transmitter or receiver; and generate an obscuration map from thecoordinates relative to the location of the transmitter or receiver.

EXAMPLE EMBODIMENTS

With reference made to FIG. 1, depicted therein is a platform 105 towhich a directional transmitter 110 is attached. In this case, platform105 is an aircraft, and transmitter 110 is the infrared source for adirectional infrared countermeasure (DIRCM) system. While FIG. 1illustrates an aircraft and a transmitter mounted thereto, thetechniques of the present disclosure are not so limited. Instead, thetechniques described herein may be applied to any transmitter orreceiver device with a field of view or field of regard (FOR) in whichobscurations may be arranged. The application of the disclosedtechniques to DIRCM systems is just one example embodiment thereof.

Transmitter 110, according to the present example embodiment, directsinfrared beams 115 a and 115 b towards detected threats 120 a and 120 b.As illustrated, infrared beam 115 a is able to contact or “lase” threat120 a, while infrared beam 115 b is prevented or obscured from lasingthreat 120 b due to the location of tailfin 105 a of aircraft 105. Inother words, tailfin 105 a is an obscuration within the field of view orFOR of transmitter 110. An obscuration refers to a feature within thefield of regard of a transmitter, such as the fuselage, tail or wing ofan aircraft serving as the platform for the transmitter that preventsthe transmitter from “seeing” or engaging an incoming threat. Featureswhich do not change position in the transmitter FOR are defined as hardobscurations while features with moving parts (e.g. landing gear, flaps,fins, etc.) or that may flex (e.g. wings) may be considered temporaryobscurations and may be referred to as soft obscurations. Similarly, asillustrated in FIG. 2, a sensor or receiver 210 may have an FOR 215which is limited by obscurations 205 a and 205 b, in this case a tailfinand canopy, respectively, of aircraft 205 which serves as the platformfor sensor/receiver 210. As with FIG. 1, the techniques of the presentdisclosure are not limited to receivers mounted to aircraft, orreceivers used to implement DIRCM systems. For example, the techniquesof the present disclosure may be used to locate obscurations in FORs forany sensor, wide-angle camera, narrow-angle camera, lens, imagingdevice, or other type of receiver configured to acquire date within anFOR. Accordingly, “receiver” as used herein is broadly construed toencompass such sensor, imaging, and other receiver devices that sense orreceive throughout an FOR.

In order to compensate for these obscurations within FORs oftransmitters and sensors/receivers, maps of these obscurations, orobscuration maps may be used. Obscuration maps are used to properlyallocate transmitters and sensor/receivers to ensure a full FOR, reducefalse alarms, and ensure that transmitters, such as transmitter 110 ofFIG. 1, do not lase portions of their platform, such as tail fine 105 aof FIG. 1.

One technique for creating obscuration maps may involve markingtangential points created by a laser mounted at the transmitter orsensor/receiver location. The use of such laser detection is bothtime-consuming and labor intensive. Specifically, a Laser Pointer Tool(LPT), mounts a laser pointer in the exact location of the transmitteror sensor/receiver. The LPT is used to mark hundreds of physical spots(tangent points) utilizing masking tape and a marker pen. A lasertracker and other metrology equipment is then used to measure and mapout the points relative to the transmitter location. Depending on thenumber of transmitters and their installed locations, this technique maytake hundreds of hours to perform (e.g., roughly 240 labor hours offield effort with up to five days of exclusive access on the aircraft,followed by roughly 120 hours of post-processing). Obviously, suchtechniques are labor intensive and contain sources of variation such astangent point identification and corner cube placements, as well as dataprocessing.

The techniques of the present disclosure utilize one or more cameras,which may be off-the-shelf (OTS) cameras such as GoPro® cameras,arranged at the transmitter or sensor location. A novel fixture may beutilized to position the camera or cameras in desired locations. Thetechniques to be described herein include taking photographs of theobscuration field over the entire FOR of the transmitter orsensor/receiver. The photographs may then be uploaded to a computersystem implementing a post-processing software tool that is utilized totrace the obscuration edges. The techniques of the present disclosuremay require significantly less effort in the field (e.g., about 48 laborhours and only two days on the aircraft) and an equivalentpost-processing time of roughly 120 hours.

With reference now made to FIG. 3, depicted therein is an exampleprocess 300 for generating an obscuration map for a transmitteraccording to the techniques described herein. The process begins inoperation 305 in which a fixture arranged at the transmitter mount of,for example, a DIRCM system is used in conjunction with a camera tocollect image data of the FOR of the transmitter. An example of such afixture will be described in more detail with reference to FIG. 5,below. Though, as noted above, other example embodiments may arrange thefixture at a mount for any transmitter, receiver or sensor configured totransmit over or image with an FOR. The image data acquired may beacquired by altering the orientation of the camera within thetransmitter mount via the fixture to acquire image data for the entireFOR of the transmitter. According to such an embodiment, the fixture maybe configured to position a camera in a plurality of orientations thatwill result in the camera acquiring image data for the entire FOR of thetransmitter. According to some example embodiments, the image data maycomprise a series of discrete digital photographs. According to otherexample embodiments, the fixture may be configured to continuously movethe camera through different orientations to generate a singlephotograph or image of the FOR.

In operation 310, an obscuration in the image data is determined. Forexample, as illustrated in FIG. 4, the image data date acquired inoperation 305 may be uploaded to a software tool and presented to a userwho outlines the location of obscuration within the image. Specifically,as illustrated in FIG. 4, user interface 400 of such a software toolprovides an image portion 405 that displays image data of the FOR of atransmitter to a user. Image portion 405 includes an outline 410 of anobscuration 415 within image portion 405. The outline 405 of obscuration415 may be automatically generated utilizing techniques such as edgerecognition within image portion 405. According to other embodiments, auser may define outline 410 within image portion 405. The user may alsobe able to indicate additional pixels that will correspond to atemporary or soft obscuration, and mark these separately for inclusionin the obscuration map as a soft obscuration. More specifically, a usermay provide outline 410, which outlines hard obscurations, andseparately provide a separate outline indicating the extent of the softobscuration. According to other example embodiments, two images may betaken at the same fixture orientation, but with the soft obscurationpositioned differently. For example, a first image may be taken with awing or fin positioned in one orientation, and a second image may betaken with a wing or fin in a second orientation. The obscurationsindicated in these two images may be used to determine the locations forthe soft obscurations. According to still other example embodiments, theuser may be able to indicate when an obscuration is associated with anelement that flexes, and such locations may be “padded” to ensure thatthe flexing of the element is taken into account in the obscuration map.

Without outline 410 determined, the pixels within the outline aredetermined to be an obscuration within the image 405. These pixels aregiven a coordinate within the image, or given a coordinate within the“pixel space” defined by the image. Using image selection portion 420,the user may be able to select different image data sets that, whencombined, comprise the entire FOR of the transmitter.

Returning to FIG. 3, in operation 315, the obscurations determined inthe pixel space are then determined as a vector in a reference framerelative to the fixture to which the camera is attached to acquire thepictures as described above with reference to operation 305.Specifically, because the fixture is arranged at the transmitterlocation (an example of such a fixture is described in detail below withreference to FIG. 5), the fixture may be used to determine the positionor orientation of the camera used to acquire the image, as well asspecific pixels within each image. This camera arrangement may be usedto determine a corresponding positioning or orientation of thetransmitter that would result in the transmitter being directed towardsthe obscurations. This positioning or orienting may be described using avector of values relative to the transmitter location. For example, alocation within outline 410 of FIG. 4, corresponding to a portion of anobscuration, may be given a vector value corresponding to a position ororientation of the transmitter that would be directed towards thatobscuration. Such a vector may correspond to a polar angle and anazimuthal angle of the transmitter that would direct the transmittertowards the obscuration. Furthermore, as will be described in greaterdetail below with reference to FIG. 5, the image data may be acquired byrotating a camera through an azimuthal angle and a polar angle. Therotation of the camera through these azimuthal and polar angles may beexamples of the positions or orientations described above. The imageacquisition optics of the camera may be slightly off center at eachangular position. Accordingly, operation 315 may translate the vectorsacquired in operation 310 such that obscurations determined from imagedata acquired at different orientations are all indicated using vectorsfrom a common reference point on or relative to the fixture ortransmitter when installed on the platform.

In operation 320, the vector describing the location of the obscurationin coordinates relative to the transmitter is determined as a vector incoordinates relative to the aircraft, or other platform upon which thetransmitter is arranged. According to some example embodiments, thevector in transmitter coordinates and the vector in aircraft coordinatesmay be the same value, such as when the techniques described herein areapplied to an aircraft with a single transmitter. According to otherexample embodiments, such as embodiments in which the techniquesdescribed herein are applied to an aircraft with multiple transmitters,the aircraft coordinates may be a coordinate system centered at alocation different from that of the location of one or more of thetransmitters. Accordingly, operation 320 translates the vector intransmitter coordinates to a vector in aircraft coordinates.

Finally, in operation 325, obscurations located and mapped to aircraftcoordinates are combined into an obscuration map for the aircraft. Theobscuration map may then be stored in a memory of a processing system ofthe aircraft and used in the operation of the DIRCM system. Once storedin the memory, the obscuration map may be utilized by the processingsystem of the aircraft to reduce false alarms, to allow the aircraft toproperly allocate transmitters, and to increase the operational life ofthe transmitter and received systems.

With reference now made to FIG. 5, depicted therein is an examplefixture 500 that is configured for use with the techniques describedherein. Fixture 500 includes five main parts: mounting plate 520,azimuthal positioning plate 540, mounting arm 560, polar positioningmount 580, and camera mount 590.

As illustrated in FIG. 5, mounting plate 520 is configured to arrangefixture 500 within the transmitter mounting structure (not shown) of aplatform to which a DIRCM system is mounted. If the transmitter mountingsystem includes a lens or dome assembly, the fixture 500 may be usedwith the lens or dome assembly in place. According to other exampleembodiments, the lens or dome assembly of the transmitter moundingstructure may be removed during use of the fixture 500. Furthermore,while fixture 500 is configured to be arranged within the transmittermounting structure in place of the transmitter, other exampleembodiments may position the fixture 500 in the transmitter mountingstructure with the transmitter still in place.

According to the example of FIG. 5, mounting plate 520 includes one moremounting pins 522 which allow fixture 500 to be positioned and securedwithin the transmitter mounting structure of the DIRCM platform.According to other example embodiments, mounting plate 520 may beconfigured with holes to receive, for example, pins or screwsincorporated into the transmitter mounting structure. Similarly, otherexample embodiments of mounting plate 520 may be configured with holesor threaded holes through which screws or bolts may be used to securemounting plate 520 to corresponding threaded holes in the transmittermounting structure.

Arranged within mounting plate 520 is azimuthal positioning plate 540.Azimuthal position plate 540 is rotatably mounted to mounting plate 520so that the fixture may be used to image obscurations at a plurality ofdifferent azimuthal angles. For example, a bearing (not pictured) may bepress-fit into mounting plate 520, and azimuthal positioning plate 540may be mounted to the bearing so that it may easily rotate relative tomounting plate 520. Once appropriately positioned relative to mountingplate 520, azimuthal positioning plate 540 may be secured to mountingplate 520 via clamps 522 a and 522 b, as well as alignment notches 524 aand 524 b and registration holes 542 a-i. Specifically, one or more ofregistration holes 542 a-i is aligned with one or more of alignmentnotches 524 a and 524 b. Clamps 522 a and 522 b may be used to secureazimuthal position plate 540 at this position while a camera mounted incamera mount 590 is used to image obscurations at one or more polarangles. After imaging obscurations at this first azimuthal angle, clamps522 a and 522 b may be loosened, azimuthal position plate 540 may berotated so that different registrations holes 542 a-i align withalignment notches 524 a and 524 b, clamps 522 a and 522 b may beretightened, and imaging of obscurations may take place at this newazimuthal angle. This process may repeat for a desired number ofazimuthal angles.

Also included in fixture 500 is mounting arm 560 via which the camera ismounted to azimuthal positioning plate 540. According to exampleembodiments, mounting arm 560 serves to attach the camera to theazimuthal positioning place 540 and also raise the camera to a positionabove mounting plate 520 that corresponds to a height of a DIRCMtransmitter when it is positioned within the transmitter mountingstructure. As illustrated in FIG. 5, mounting arm 560 is secured toazimuthal positioning plate 540 via bolts 562 a-d, though otherstructures known to those skilled in the art may also be used. Mountingarm 560 may also be integrally formed with azimuthal positioning place540.

Attached to mounting arm 560 is polar positioning mount 580. Polarpositioning mount 580 is configured to position the camera such that thecamera may be directed at a plurality of polar angles. For example, ateach azimuthal position of the camera, the camera may also be positionedto image at a plurality of polar angles, thereby allowing the camera toimage the entire field of regard of the transmitter. In order toposition the camera at the plurality of polar angles, polar positioningmount 580 is configured with a series of holes 582 a-l. Correspondingholes are included in mounting arm 560. By arranging screws, bolts, pinsor other means of securing polar positioning mount 580 to mounting arm560, the camera may be positioned at one or more pre-determined polarorientations. By combining a number of azimuthal positions via azimuthalpositioning plate 540 with a number of polar positions via polarpositioning mount 580, the camera may be oriented to image the entireFOR of the transmitter. According to some example embodiments, the rangeof motion permitted by azimuthal position plate 540 and polarpositioning mount 580 may be configured to match the range of motion ofthe transmitter. According to other example embodiments, the range ofmotion permitted by azimuthal position plate 540 and polar positioningmount 580 may be configured to provide a range of motion that is greaterthan that provided by the transmitter.

Finally, included in fixture 500 is camera holder 590. The exampleembodiment of FIG. 5 illustrates camera holder 590 as having aclam-shell design in which a camera is enclosed on either side byportions of camera holder 590, and screws or bolts 592 a and 592 bsecure the camera within the clam shell portions of camera holder 590.Also include in cameral holder 590 are a series of orifices 594 a-cwhich permit access to the manual controls, optical elements, andelectrical elements of the camera.

Fixture 500 of FIG. 5 is configured to be manually oriented through aseries of azimuthal and polar positions, elements 522 a-b, 524 a-b, 542a-1, and 582 a-1 allowing a user to position and secure fixture 500 atthe orientations needed to image the entire FOR of the transmitter. Thecamera may be controlled to image at each of these orientations eitherremotely or via access to the camera via orifices 594 a-c. As understoodby the skilled artisan, one or more of elements 522 a-b, 524 a-b, 542a-1, and 582 a-1 may be replaced or supplemented with one or moreactuators. These actuators, along with the camera, may be computercontrolled to automate the process of imaging the FOR of thetransmitter. In such example embodiments, the camera may be continuouslymoved through a plurality of azimuthal and polar angles to generate apanoramic view of the FOR of the transmitter.

With reference now made to FIG. 6, depicted therein is an alternativefixture 600 used according to the techniques described herein. Ingeneral, fixture 600 is constructed and operates in a manner similar tothat of fixture 500 of FIG. 5, and therefore, like reference numeralshave been used to refer to like elements. Fixture 600 differs from thatof fixture 500 of FIG. 5 in that camera holder 690 is configured to holdtwo cameras instead of the one camera of camera holder 590 of FIG. 5. Aswill be described in greater detail below with reference to FIG. 8, byusing two cameras, three dimensional information including the distancefrom the transmitter to the imaged obscurations may be derived from theimage data acquired by the cameras. This results in some structuraldifferences between mounting arm 660, polar positioning mount 680 andcamera holder 690 and the corresponding structures, polar positioningmount 580, mounting arm 560 and camera holder 590 of FIG. 5.

First, in order to accommodate a second camera, camera holder 690includes two clam shell enclosures, secured with bolts 692 a-b and 692c-d, respectfully, and containing two sets of orifices 694 a-b and 694c-d, respectively.

Second, polar positioning mount 580 of FIG. 5 is positioned on mountingarm 560 such that the optical sensor of the camera is positioned wherethe output of the DIRCM transmitter would be positioned. On the otherhand, polar positioning mount 680 is positioned on mounting arm 660 suchthat the midpoint between the optical sensors of the two cameras ispositioned where the output of the DIRCM transmitter would bepositioned. An example of these differences in arrangement isillustrated in FIG. 7. As shown in FIG. 7, transmitter height 702 alignswith the optical element of 704 of single camera fixture 700 a, whiletransmitter height 702 aligns with the midpoint between optical elements706 and 708 of fixture 700 b.

With reference now made to FIG. 8, depicted therein is a process forgenerating an obscuration map using a fixture like fixture 600 of FIG.6. Specifically, depicted in FIG. 8 is an example process 800 forgenerating an obscuration map according to the techniques describedherein that utilizes stereoscopic cameras to generate the obscurationmap.

The process begins in operation 805 in which a fixture arranged at thetransmitter mount of, for example, a DIRCM system is used in conjunctionwith a plurality of cameras to collect image data of the FOR of thetransmitter. Though, as noted above, other example embodiments mayarrange the fixture at a mount for any transmitter, receiver or sensorconfigured to transmit over or image with an FOR. More specifically thefixture is configured to position two camera, such as fixture 600 ofFIG. 6. Other example embodiments may utilize fixtures with more thantwo cameras. The image data acquired may be acquired from each of thetwo cameras from a plurality of positions so that the image dataincludes image data for the entire FOR of the transmitter. Morespecifically, pairs of images are acquired for each position such thateach camera acquires image data for each position, but the image dataacquired by the two cameras is slightly offset from each other. As withthe process of the example embodiment of FIG. 3, the image data acquiredby the pair of cameras may comprise a series of discrete digitalphotographs. More specifically, the image data may comprises a series ofpairs of images acquired by each of the two cameras. According to otherexample embodiments, the fixture may be configured to move the twocameras through a continuous path to generate a pair of photographs orimages of the entire FOR.

In operation 810, a three dimensional representation of the image datais generated. Because two pairs of images have been generated by thepairs of cameras, it is possible to generate three dimensional imagedata from pairs of two-dimensional image data. For example, stereotriangulation may be used to determine depth data of the pixels of imagedata acquired using the pairs of (i.e., stereoscopic) cameras.Specifically, the depth to points in the image data, for example fromthe center point of the line between the focal points of the twocameras, may be determined. In order to determine these depthmeasurements, corresponding points in the pairs of image data aredetermined. Finding the corresponding portions of the shared images maybe done manually, with a user selecting corresponding pixels in the twoimages, or image processing may be utilized to automate this process.

In order to determine the depth information, example embodiments ofoperation 810 may first rectify the pairs of image data. Rectificationis a transformation process used to project the pairs of image data ontoa common image plane. For example, X and Y rotations may be used to putthe images on the same plane, scaling may be used to make the pairs ofimage data the same size, and Z rotation and skew adjustments may makepixel rows of the image data directly line up. Calibrated andun-calibrated rectification processes may be utilized. Un-calibratedstereo image rectification is achieved by determining a set of matchedinterest points, estimating the fundamental matrix for the two cameras,and then deriving two projective transformations. The fundamental matrixis a relationship between any two images of the same scene thatconstrains where the projection of points from the scene can occur inboth images. Calibrated stereo rectification uses information from astereo camera calibration process. Stereo camera calibration is used todetermine the intrinsic parameters and relative location of cameras in astereo pair, and this information is then used for stereo rectificationand 3-D reconstruction. Such a calibration process may include takingimages of a known pattern (such as a checkerboard pattern) at a knowndepth. Stereoscopic images of this known pattern at the known depth maybe used to determine the intrinsic parameters and relative location ofcameras, which may then be used to rectify the obscuration image datapairs to generate the three-dimensional representation of the imagedata.

Once three-dimensional representations of the image data are generated,an obscuration in the image data is determined in operation 815. Forexample, the obscurations may be outlined by a user in a system likethat illustrated and as described above with reference to FIG. 4.Because the pairs of image data have been processed in operation 810,the user interface of FIG. 4 need only display the image data from oneof the two cameras. According to other example embodiments, the user maybe asked to indicate and/or outline the obscurations in each pair ofimage data. Once the obscuration is indicated, a three-dimensionalcoordinate or coordinates may be determined for the obscuration.Depending on how the three-dimensional representation is generated inoperation 810, the three-dimensional coordinate or coordinates of theobscuration may take on different forms. For example, the coordinate orcoordinates may be spherical coordinate values that include an azimuthalorientation of the center point between the pairs of cameras, a polarorientation of the center point between the pairs of cameras and aradial depth to the obscuration from the center point between the pairsof cameras. According to other example embodiments, the coordinate orcoordinates may be three-dimensional Cartesian coordinates with anorigin at the center point between the pairs of cameras.

In operation 820, the obscurations locations are determined asthree-dimensional coordinates in a reference frame relative to thefixture to which the camera is attached to acquire the pictures asdescribed above with reference to operation 805. Specifically, due tothe rotation of, for example, polar positioning mount 680 of FIG. 6, thethree dimensional coordinates determined in operation 815 may beslightly different at different polar orientations. Similarly, due tothe rotation of azimuthal positioning plate 540 of FIG. 6, the threedimensional coordinates determined in operation 815 may be slightly bedifferent at different azimuthal orientations. Accordingly, in operation820, the three dimensional coordinates acquired in operation 815 may bemapped to coordinates from a fixed location on or relative to thefixture or the location of the transmitter when installed in theplatform.

In operation 825, the coordinates describing the location of theobscuration in coordinates relative to the transmitter are determined incoordinates relative to the aircraft, or other platform upon which thetransmitter is arranged. According to some example embodiments, thecoordinates in transmitter coordinates and the coordinates in aircraftcoordinates may be the same value, such as when the techniques describedherein are applied to an aircraft with a single transmitter. Accordingto other example embodiments, such as embodiments in which thetechniques described herein are applied to an aircraft with multipletransmitters, the aircraft coordinates may be a coordinate systemcentered at a location different from that of the location of one ormore of the transmitters. Accordingly, operation 825 translates thecoordinates in transmitter coordinates to coordinates in aircraftcoordinates.

Finally, in operation 830, obscurations located and mapped to aircraftcoordinates are combined into an obscuration map for the aircraft.

Through the use of processes like those of the example embodiments ofFIGS. 3 and 8, utilizing fixtures like those illustrated in FIGS. 5-7and/or utilizing tools like the one illustrated in FIG. 4, obscurationmaps may be generated in ways that provide substantial benefits overrelated art techniques. Depending on the number of transmitters andtheir installed locations, the techniques of the present disclosure mayrequire significantly less effort in the field. For example, thetechniques of the present disclosure may result in a greater than 50%reduction in man hours in the field. Furthermore, the equipmentnecessary to perform the techniques described herein may providesignificant cost savings over those of related art techniques. Asdescribed above, the techniques of the present disclosure utilize one ormore cameras, which may be OTS cameras such as GoPro® cameras. Such OTScameras are significantly less expensive than the laser range findersutilized in related art techniques. Additionally, even though the OTScameras used in the present techniques may suffer from variations, suchas variations introduced via image magnification, ambient lighting,glare, edge definition/camera resolution, and data processing, theobscuration maps generated from the present techniques are shown to beof comparable accuracy to those generated by more cost and timeintensive systems.

Finally, illustrated in FIG. 9 is a computer system configured toimplement the techniques described herein. The computer system 901 maybe programmed to implement a computer based device, such as a deviceconfigured to implement at tool like that illustrated in FIG. 4, or atool used to perform processing corresponding to the operations of FIGS.3 and 8. The computer system 901 includes a bus 902 or othercommunication mechanism for communicating information, and a processor903 coupled with the bus 902 for processing the information. While thefigure shows a single block 903 for a processor, it should be understoodthat the processors 903 represent a plurality of processing cores, eachof which can perform separate processing. The computer system 901 alsoincludes a main memory 904, such as a random access memory (RAM) orother dynamic storage device (e.g., dynamic RAM (DRAM), static RAM(SRAM), and synchronous DRAM (SD RAM)), coupled to the bus 902 forstoring information and instructions to be executed by processor 903. Inaddition, the main memory 904 may be used for storing temporaryvariables or other intermediate information during the execution ofinstructions by the processor 903.

The computer system 901 further includes a read only memory (ROM) 905 orother static storage device (e.g., programmable ROM (PROM), erasablePROM (EPROM), and electrically erasable PROM (EEPROM)) coupled to thebus 902 for storing static information and instructions for theprocessor 903.

The computer system 901 also includes a disk controller 906 coupled tothe bus 902 to control one or more storage devices for storinginformation and instructions, such as a magnetic hard disk 907, and aremovable media drive 908 (e.g., floppy disk drive, read-only compactdisc drive, read/write compact disc drive, compact disc jukebox, tapedrive, and removable magneto-optical drive). The storage devices may beadded to the computer system 901 using an appropriate device interface(e.g., small computer system interface (SCSI), integrated deviceelectronics (IDE), enhanced-IDE (E-IDE), direct memory access (DMA), orultra-DMA).

The computer system 901 may also include special purpose logic devices(e.g., application specific integrated circuits (ASICs)) or configurablelogic devices (e.g., simple programmable logic devices (SPLDs), complexprogrammable logic devices (CPLDs), and field programmable gate arrays(FPGAs)), that, in addition to microprocessors and digital signalprocessors may individually, or collectively, are types of processingcircuitry. The processing circuitry may be located in one device ordistributed across multiple devices.

The computer system 901 may also include a display controller 909coupled to the bus 902 to control a display 910, such as a cathode raytube (CRT), Liquid Crystal Display (LCD) or other now known orhereinafter developed display technologies, for displaying informationto a computer user. The computer system 901 includes input devices, suchas a keyboard 911 and a pointing device 912, for interacting with acomputer user and providing information to the processor 903. Thepointing device 912, for example, may be a mouse, a trackball, or apointing stick for communicating direction information and commandselections to the processor 903 and for controlling cursor movement onthe display 910. Input devices 911 and 912 may be used by a user toidentify obscurations as described above with reference to FIG. 4. Forexample, pointing device 911 may be used to define outline 410. Pointingdevice 911 may also be used within selection portion 420 of FIG. 4 toselect different image data sets that, when combined, comprise theentire FOR of the transmitter. Similarly, display 910 may be used todisplay user interface 400 of FIG. 4. In addition, a printer may provideprinted listings of data stored and/or generated by the computer system901.

The computer system 901 performs a portion or all of the processingsteps of the process in response to the processor 903 executing one ormore sequences of one or more instructions contained in a memory, suchas the main memory 904. Such instructions may be read into the mainmemory 904 from another computer readable medium, such as a hard disk907 or a removable media drive 908. One or more processors in amulti-processing arrangement may also be employed to execute thesequences of instructions contained in main memory 904. In alternativeembodiments, hard-wired circuitry may be used in place of or incombination with software instructions. Thus, embodiments are notlimited to any specific combination of hardware circuitry and software.

As stated above, the computer system 901 includes at least one computerreadable medium or memory for holding instructions programmed accordingto the embodiments presented, for containing data structures, tables,records, or other data described herein. Examples of computer readablemedia are compact discs, hard disks, floppy disks, tape, magneto-opticaldisks, PROMs (EPROM, EEPROM, flash EPROM), DRAM, SRAM, SD RAM, or anyother magnetic medium, compact discs (e.g., CD-ROM), or any otheroptical medium, punch cards, paper tape, or other physical medium withpatterns of holes, or any other medium from which a computer can read.

Stored on any one or on a combination of non-transitory computerreadable storage media, embodiments presented herein include softwarefor controlling the computer system 901, for driving a device or devicesfor implementing the process, and for enabling the computer system 901to interact with a human user. Such software may include, but is notlimited to, device drivers, operating systems, development tools, andapplications software. Such computer readable storage media furtherincludes a computer program product for performing all or a portion (ifprocessing is distributed) of the processing presented herein.

The computer code devices may be any interpretable or executable codemechanism, including but not limited to scripts, interpretable programs,dynamic link libraries (DLLs), Java classes, and complete executableprograms. Moreover, parts of the processing may be distributed forbetter performance, reliability, and/or cost.

The computer system 901 also includes a communication interface 913coupled to the bus 902. The communication interface 913 provides atwo-way data communication coupling to a network link 914 that isconnected to, for example, a local area network (LAN) 915, or to anothercommunications network 916 such as the Internet. For example, thecommunication interface 913 may be a wired or wireless network interfacecard to attach to any packet switched (wired or wireless) LAN. Asanother example, the communication interface 913 may be an asymmetricaldigital subscriber line (ADSL) card, an integrated services digitalnetwork (ISDN) card or a modem to provide a data communicationconnection to a corresponding type of communications line. Wirelesslinks may also be implemented. In any such implementation, thecommunication interface 913 sends and receives electrical,electromagnetic or optical signals that carry digital data streamsrepresenting various types of information.

The network link 914 typically provides data communication through oneor more networks to other data devices. For example, the network link914 may provide a connection to another computer through a local arenetwork 915 (e.g., a LAN) or through equipment operated by a serviceprovider, which provides communication services through a communicationsnetwork 916. The local network 914 and the communications network 916use, for example, electrical, electromagnetic, or optical signals thatcarry digital data streams, and the associated physical layer (e.g., CAT5 cable, coaxial cable, optical fiber, etc.). The signals through thevarious networks and the signals on the network link 914 and through thecommunication interface 913, which carry the digital data to and fromthe computer system 901 maybe implemented in baseband signals, orcarrier wave based signals. The baseband signals convey the digital dataas unmodulated electrical pulses that are descriptive of a stream ofdigital data bits, where the term “bits” is to be construed broadly tomean symbol, where each symbol conveys at least one or more informationbits. The digital data may also be used to modulate a carrier wave, suchas with amplitude, phase and/or frequency shift keyed signals that arepropagated over a conductive media, or transmitted as electromagneticwaves through a propagation medium. Thus, the digital data may be sentas unmodulated baseband data through a “wired” communication channeland/or sent within a predetermined frequency band, different thanbaseband, by modulating a carrier wave. The computer system 901 cantransmit and receive data, including program code, through thenetwork(s) 915 and 916, the network link 914 and the communicationinterface 913. Moreover, the network link 914 may provide a connectionthrough a LAN 915 to a mobile device 917 such as a personal digitalassistant (PDA) laptop computer, or cellular telephone.

The above description is intended by way of example only. Although thetechniques are illustrated and described herein as embodied in one ormore specific examples, it is nevertheless not intended to be limited tothe details shown, since various modifications and structural changesmay be made within the scope and range of equivalents of the claims.

What is claimed is:
 1. A method comprising: arranging a camera on atransmitter or receiver mount of a vehicle, wherein the transmitter orreceiver mount is configured to provide a transmitter or receiver with afield of regard; capturing, via the camera, image data of the field ofregard; determining a location of an obscuration caused by a portion ofthe vehicle within the field of regard from the image data; andgenerating an obscuration map of obscurations within the field of regardbased upon the location of the obscuration within the field of regard;storing the obscuration map in a memory of a processing system of thevehicle; and utilizing the obscuration map, via the processing system ofthe vehicle, to reduce false alarms, properly allocate transmitters orincrease an operation life of the transmitter or receiver, whereindetermining the location of the obscuration comprises: generating animage from the image data; presenting the image to a user via a userdisplay device; receiving a user input comprising an indication of thelocation of the obscuration in a pixel space of the image; determiningthe location of the obscuration in coordinates relative to the camera ofthe location of the obscuration in the pixel space of the image;determining a vector of the location of the obscuration in coordinatesrelative to the transmitter or the receiver; and determining a vector ofthe location of the obscuration in coordinates relative to the vehicle.2. The method of claim 1, wherein transmitter or receiver comprises adirectional infrared countermeasure transmitter or receiver.
 3. Themethod of claim 1, wherein determining the location of an obscurationwithin the field of regard comprises determining an angular location ofthe obscuration relative to the camera and a distance from the camera.4. The method of claim 1, wherein arranging the camera comprisesarranging a plurality of cameras on the transmitter or receiver mount;and wherein capturing image data of the field of regard comprises:capturing image data from each of the plurality of cameras, andgenerating three-dimensional data from the image data from each of theplurality of cameras; and wherein determining the location of theobscuration comprises determining a three-dimensional location of theobscuration from the three-dimensional data.
 5. The method of claim 1,wherein capturing image data of the field of regard comprises capturinga plurality of photographs.
 6. The method of claim 1, whereindetermining the location of the obscuration comprises determining alocation of a permanent obscuration.
 7. The method of claim 1, whereindetermining the location of the obscuration comprises determining alocation of a temporary obscuration.
 8. The method of claim 1, whereincapturing the image data of the field of regard comprises repositioningthe transmitter or receiver mount through a plurality of positions sothat the camera acquires image data from the entire field of regard. 9.The method of claim 1, wherein arranging the camera comprises arranginga pair of cameras on the transmitter or receiver mount; whereincapturing image data of the field of regard comprises capturing imagedata from each of the pair of cameras to generate pairs of images;wherein presenting the image to the user comprises presenting the pairsof images to the user via the user display device; and wherein receivingthe user input comprises receiving the user input comprising a pair ofindications of coordinates of the obscuration within the pair of images.10. The method of claim 1, wherein a coordinate system for thecoordinates relative to the transmitter or the receiver is the samecoordinate system as the coordinate system for the coordinates relativeto the vehicle.
 11. The method of claim 1, wherein determining thelocation of the obscuration further comprises rectifying a pair ofimages that contain image data for the obscuration.
 12. The method ofclaim 11, wherein the rectifying comprises projecting image data fromeach of the pair of images onto a common image plane.
 13. The method ofclaim 12, wherein the rectifying further comprises providing one or moreof a rotation or a skew adjustment to align the image data from each ofthe pair of images in the common image plane.
 14. The method of claim 11wherein the rectifying comprises a calibrated rectification.
 15. Themethod of claim 11 wherein the rectifying comprises an uncalibratedrectification.
 16. The method of claim 9, wherein determining thelocation of the obscuration further comprises rectifying a pair ofimages that contain image data for the obscuration from the pair ofcamera.
 17. The method of claim 16, wherein the rectifying comprisesprojecting image data from each of the pair of images onto a commonimage plane.
 18. The method of claim 17, wherein the rectifying furthercomprises providing one or more of a rotation or a skew adjustment toalign the image data from each of the pair of images in the common imageplane.
 19. The method of claim 12 wherein the rectifying comprises acalibrated rectification.